   public static void main(String[] args){
        String s1 = "welcome to xpu";
        String s2 = "come";
        System.out.println(removeChars(s1, s2));
   }

	//删除第一个字符串中出现的第二个字符串中的字符
    public static ArrayList<Character> removeChars(String str1, String str2){
        ArrayList<Character> arrayList = new ArrayList<>();
        for(int i = 0; i < str1.length(); i++){
            char ch = str1.charAt(i);
            if(str2.contains(ch+"")){
                continue;
            }else{
                arrayList.add(ch);
            }
        }
        return arrayList;
    }